382 GENERATION. 



introduced into one of the divided vessels of the uterine 

 walls, and air is forced in by gentle insufflation. By this 

 process, the venous sinuses of the uterus itself are first filled, 

 next, the deeper portions of the placenta, and finally, " the 

 bubbles of air insinuate themselves everywhere between the 

 foetal tufts, and appear in the most superficial portions of the 

 placenta,, immediately underneath the transparent chorion. 

 If the chorion be now divided at any point by an incision, 

 passing merely through its own thickness, the air, which was 

 confined beneath it in the placental sinuses, will escape, and 

 rise in bubbles to the surface of the water. Such an experi- 

 ment shows conclusively that the placental sinuses communi- 

 cate freely with the uterine vessels, occupy the entire thick- 

 ness of the placenta, and are equally extensive with the tufts 

 of the foetal chorion." Dalton farther states that the uterine 

 vessels, as they penetrate the placenta, have an exceedingly 

 oblique direction, and that their orifices may be easily over- 

 looked, but can be seen by careful inspection. 1 



"We have no doubt with regard to the accuracy of the ob- 

 servations of Dalton, and we conceive that they have settled 

 the question of the existence of a true maternal portion of 

 the placenta. In corroboration of this, in 1864, we examined 

 the uterus, with the placenta attached, of a woman who died 

 in the latter months of pregnancy, in the presence of the late 

 Prof. G. T. Elliot and Prof. J. P. White, and forced air from 

 the uterine sinuses throughout the entire thickness of the 

 placenta, between the foetal tufts. In view of these facts, 

 concerning which there can be no doubt, it seems unnecessary 

 to discuss the more or less theoretical views of writers who 

 have not made injections of the uterus with the placenta at- 

 tached. The observations of Dalton have since been con- 

 firmed by numerous anatomists, among the latest of whom 

 we may mention Prof. Turner, Dr. J. Matthews Duncan, 

 and M. Laure; so that we must consider the fact of . an 



1 DALTON, Anatomy of the Placenta. From the American Medical Monthly, 

 New York, July, 1858, pp. 12, 14. 



